Teva, the world’s largest generic drugs group, is redoubling its focus on the quality of its medicines as it steps up efforts to defend its own blockbuster patented multiple sclerosis medicine from competition by stressing its extensive safety record and distinctive characteristics. In one of his first interviews since taking over as chief executive of the Israeli-based company in May, Jeremy Levin argued that its biological treatment Copaxone was “complex” and that any rival producing a “biosimilar” version should be required to conduct extensive clinical trials to prove its equivalent.